After the box is exploited and you have Meterpreter on the payload you can begin to use.

There are many extenstions that can be used. Different extentions provide different uses.

1. Fs
Provides interaction with the filesystem on the remote machine.
2. Net
Provides interaction with the network stack on the remote machine.
3. Process
Provides interaction with processes on the remote machine.
4. Sys
Provides interaction with the environment on the remote machine.

Here is how you load them. use -m Process
loadlib: Loading library from ’ext950591.dll’ on the remote machine.

There is a lot you can do but I’m just going to show the what I use the most.
Below will get you a cmd prompt on machine.(assuming its windows)